Evaluate. Un=(-1)^n n+1/2

Question

Help pls

Answer 1

again? Not sure what you want. The first few terms are

U1 = (-1)^1 (1+1)/2 = -1
U2 = (-1)^2 (2+1)/2 = 3/2
U3 = (-1)^3 (3+1)/2 = -2
and so on

what do you mean by "evaluate Un" ?